Webpack: ReferenceError: document is not defined style-loader

I'm new to webpack and including bootstrap in my project. If I use style-loader I get a "Reference error for document not defined", otherwise if I remove style-loader and then run it, In this case I get an error on bootstrap.css file ":root" for ":"

const path = require('path');
const nodeExternals = require('webpack-node-externals');

module.exports = {
  entry: './server/index.js',

  target: 'node',

  externals: [nodeExternals()],

  output: {
    path: path.resolve('server-build'),
    filename: 'index.js'
  },

  module: {
    rules: [
      {
        test: /\.js$|jsx/,
        use: 'babel-loader'
      },
      {
        test: /\.css$/,
        loader: 'style-loader!css-loader'
      }
    ]
  }
};